Hearing aid



Nov. 8, 1960 J. LADD HEARING AID Filed May 22, 1956 INVENTOR Jon/v Lnon EZE/f/fl WOLF ll/S Affair Y r 2,959,645 Patented Nov. 1960 HEARING AD) John Ladd, 49 Ocean St., Lynn, Mass.

Filed May 22, 1956, Ser. No. 586,451

7 Claims. (Cl. 179--107) The present invention relates to a hearing aid and more particularly to a hearing aid adapted to fit entirely within the ear of the individual using it.

There is presently a great need for a hearing aid of a size sufiiciently small to fit entirely within the wearers ear and which is so constructed as to permit a ready disassembly for replacement of various component parts including the battery. It is further necessary that such a structure possess sufiicient gain and fidelity over a wide band width.

The present invention supplies such a need by providing a hearing aid contained entirely within a case which fits within the ear and ear canal. In this invention a microphone, battery, amplifier and receiver are secured in operative adjacent relationships within the casing in such :a manner. as to provide a rugged structure capable of developing the necessary gain and possessing the necessary fidelity of response.

The present invention also provides a structure in which the casing containing the various components of the hearing aid is shaped to readily fit within the ear and secure itself in this position without the requirements of clamps, hooks or other external engaging members. In this invention, the casing is generally shaped to fit the conch-a of the ear and is provided with a helix tip adapted to engage the crus of helix in such a manner as to coopeiate with the other portion of the casing to provide a snug and secure fit. In this invention, the helix tip is removably secured to the other portions of the casing so .that a wide range of adjustable sizes may be provided by the simple expedient of replacing the helix tip with one of another size.

The present invention also provides a;receiyer which is adapted to integrally fit the casing of the hearing aid and aid in securing this casing in position by engagement of the receiver with the side walls of the individuals ear canal.

Another feature of the present invention contemplates the use of a microphone having a toroidal shape. This microphone is of the magnetic type and has a shape adapted to fit just under the cap of the hearing aid casing. Within the opening formed by this toroidally-shaped microphone is a battery which engages a printed circuit amplifier immediately adjacent to the battery and microphone. This arrangement of component parts permits substantial space saving, thus permitting the entire unit to be contained within the ear of the wearer. These and other features of the present invention will be more clearly understood when considered in connection with the accompanying drawing in which:

Figure 1 is an exploded cross-sectional view of the various components of the present invention,

Figure 2 is a circuit diagram of the amplifier system,

and

Figure 3 is a perspective view of the hearing aid.

Referring to the drawings and in particular referring to Figure 1, there is illustrated the various components which comprise the structure of the present invention.

In this structure there is provided a casing 1 having a cap 2 designed to fit over the open or hollow section 3 of the casing 1, a microphone 4, a spring 5, a battery 6, a printed circuit amplifier 7 and a receiver 8. The casing 1 is provided with a main portion 9 having the hollow center section 3. This main portion 9 has a tubular section 10 which is shaped and directed to extend into the wears ear canal. This tubular section 10 is hollow as indicated at 11 with the hollow section 11 of suflicient diameter to contain the body section of the receiver 8. -At the upper end of the casing 1 there is provided a helix tip 12 which tip is removably secured to the wall of the casing 1 by a plurality of pins 13 projecting from the helix tip 12 and adapted to snap into recesses in the casing 1. The helix 12 may be of various sizes and shapes with the particular size and shape selected particularly for the individual wearer of the hearing aid. Thus, by proper selection of the helix tip 12, the individual hearing aid may be adapted for use by various individuals or may be used by the same individual over a prolonged period of time while the shape of his ear changes slightly or grows. The recess opening 3 is sufficiently deep to contain the various components hereinafter described which fit within it. The peripheral edge of the opening 3 is formed as a shoulder as indicated at 14 to permit a snap fastening engagement of the cap 2. This casing 1, as well as the cap 2 and portions of the receiver 8 are preferably made of a plastic material having a flesh color adapted to correspond with the color of the skin of the wearer. Further, this plastic casing should be resilient enough to withstand a certain amount of abuse which may come from accidental dropping and mishandling. The cap 2 is preferably slightly rounded at its side 15 and has a peripheral edge 16 formed with a shoulder corresponding to the shoulder on the peripheral edge 14 of the casing. There is also provided a series of perforations 17 in this cap 2 to permit the passage of sound through the cap; When this cap is snap-fastened on the casing 1, the microphone 4, battery 6, spring 5 and amplifier 7 will be snugly contained within the opening 3. In this arrangement, the battery 6 is positioned within the opening 18 formed by the toroidal shape of the microphone 4. 'This battery 6 is spring-tensioned towards proper contacts on the amplifier by the spring 5 positioned between the battery and the inner walls 19 of the cap 2. r

The amplifier 7 is provided with a pair of receptacles 20 to receive the male prongs 21 of the microphone and is also provided with a pair of receptacles 22 formed" on the other side of the plate 23 on which the printed circuit of the amplifier is formed to receive the male prongs 24 of the receiver 8. The magnetic microphone 4 is, as stated, generally toroidal in shape having formed Within its casing 25 a toroidal or annular shaped core 26 and coil 27 connected by conventional means to the male prongs 21. A series of openings 28 are provided in the face of the microphone to conduct sound waves to the annular diaphragm 29.

The battery 6 is preferably a mercury cell battery with negative and positive terminals on its face 30 adapted to contact corresponding terminals formed on the surface 31 of the plate 23. The contact between these terminals is maintained by the spring 5 which is preferably a beryllium copper spring. The printed circuit amplifier 7 is formed with the various components printed in accepted techniques upon the surface 31 of the plate 23. There are also provided recesses in this plate 23 in which transistors may be located and secured to complete the amplifier circuit. In Figure 1, the plate is illustrated as having contacts with the microphone and battery on one side and contacts for the receiver on the other side.

In Figure 2, there is shown a schematic drawing of a three-stage transistorized circuit which is suitable for their magnitude, amplification of approximately 70 db may readily be obtained. The receiver 8, which is secured within the extension of the casing 1, is electrically connected to the plate 23 as previously described and has the male prongs 24 electrically connected to the coil 50. This coil 50, positioned at the opposite end of the tubular casing 51 from the prong 24 is also positioned just behind the diaphragm 52. A second diaphragm 53 is positioned over the first diaphragm 52. These diaphragms 52 and 53 are contained within the enlarged head or tip 54 of the receiver and upon operation of the receiver cause the emission of sound waves through the opening 55 in the head 54 of the receiver directly toward the wearers eardrum.

'It is to be noted in the present invention there is no requirement at all of securing elements, such as screws. Rather, the entire structure is secured together by snap fastening and may readily be dismantled for access to any of the component parts. It should also be noted that the battery in use is of the type which may run for several months without the need of replacement.

It should further be noted that the transmitter is designed to cut down on the high frequency so as to avoid the feedback oscillation due to the proximity of the microphone and the receiver.

Having now described my invention, I claim:

1. A hearing aid adapted to fit entirely within the ear comprising a hollow casing shaped to fit within the ear concha with a portion extending into the ear canal, a receiver mounted within said portion defining an opening therethrough and shaped to extend further into the air canal, a printed circuit amplifier, a toroidal shaped microphone, a battery positioned within the opening formed by said microphone, said amplifier, microphone and battery each positioned within said casing and electrically connected to said receiver.

2. A hearing aid as set forth in claim 1 wherein a spring means is disposed in the casing and biases the said battery into electrical contact with said amplifier circuit.

3. A hearing aid as set forth in claim 1 wherein said amplifier, battery and microphone are arranged within said casing in sandwich fashion with said receiver engaging the amplifier on one side of the printed circuit and said battery and microphone engaging the printed circuit on the other side.

4. A hearing aid as set forth in claim 1 wherein said amplifier is formed by a printed circuit on a plate member with at least one transistor secured to said plate, said microphone and battery engaging said plate on one side and said receiver engaging the plate on the other side.

5. In a hearing aid a case shaped to fit within the car, a microphone shaped to fit within the case and having a toroidal shape and means forming part of the electrical system of the aid and disposed within the microphone.

6. A hearing aid adapted to fit entirely within the ear comprising a hollow casing shaped to fit within the ear concha, said casing including a tapered portion adapted to extend into the ear canal, a toroidal shaped microphone disposed in the hollow casing, a battery disposed in the central portion of the toroid, an amplifier mounted in the casing, means electrically connecting the microphone, battery, and amplifier, a recess extending through the tapered portion of the casing and terminating adjacent the amplifier, a cylindrical receiver partially disposed in the recess and electrically connected to the amplifier, the portion of the receiver disposed out of the recess adapted to extend further into the ear canal, and a cover forming part of the casing and retaining the amplifier, microphone and battery in the casing.

7. A device as defined in claim 6 further characterized by a helix tip removably secured to the side of the casing and adapted to lie within the crus of helix of the ear when the casing is disposed in the concha.

References Cited in the file of this patent UNITED STATES PATENTS 2,474,988 Sargrove July 5,1949 2,477,046 Davenport July 26, 1949 2,495,546 Posen et al. Ian. 24, 1950 2,773,941 Christiansen Dec. 11, 1956 2,787,670 Rowland Apr. 2, 1957 2,794,085 De Angelis May 28, 1957 2,808,468 Knauert Oct. 11, 1957 2,874,231 Wallace Feb. 17, 1959 FOREIGN PATENTS 723,981 Great Britain Feb. 16, 1955 922,889 Germany Dec. 9, 1954 OTHER REFERENCES Publication The New Veri'Small Paravox, 1949, IN- 41648-50M (printed circuit digest). Transistorized Hearing Aids" by I. D. Fahnestock in Electronics, April 1953, pp. 154 and 155. 

